The problem is a simple tone that cycles about 250 times per minute. Just imagine a Vibroplex key sending dits set for 250 dits per minute. It is very precise and has no related noise or hash; just a very accurate clear CW tone. Right now I hear it all over the 17M band, 18.117 for example.

I have checked numerous times for any source in the house or in the neighborhood and I just can't hear it unless I have the dipole hooked up. It is not in the house; I shut the main breaker with no result.

Smaller antennas on other radios don't hear it. When propagation is very good it is also on 15M and 12M and at times, on 20M. The signal never varies, it is very clear and precise, as I tune a higher frequency, the pitch of the tone drops. It has been there for over a year.

To bring this one back on topic--Sam, do you have a recording of the signal, and/or a waterfall image?

A recording might be helpful, yes. But if the OP is accurately describing this, it might not be necessary. It sounds to me exactly like CW dits (or dahs) being sent about 4 times per second; a "clear tone" would be an RF sine wave with no harmonics: exactly like most of us transmit when we use CW.

I think the focus should be on DFing this, rather than knowing what it is. The simpler the better, and the simplest thing I can think of is a portable radio that covers 17 meters and preferably has a BFO. Hook the dipole temporarily to the portable to ensure the portable can hear it. Then, without moving the frequency, use the built-in antenna and walk all over the neighborhood with it.

Or, if you have hams that live within a few miles with directional, rotatable beam antennas that cover 17m, see if they can hear it and in what direction. A few guys like that in the right locations could narrow this down.

The problem is a simple tone that cycles about 250 times per minute. Just imagine a Vibroplex key sending dits set for 250 dits per minute. It is very precise and has no related noise or hash; just a very accurate clear CW tone. Right now I hear it all over the 17M band, 18.117 for example.

Is it "all over" the 17m band, or is it on 18.117? Do you really hear nice, clear tone on all frequencies no matter where you tune? That would be impossible if it's a signal really on the 17m band; it might be possible if the signal is really coming in at the I.F.

Is it "all over" the 17m band, or is it on 18.117? Do you really hear nice, clear tone on all frequencies no matter where you tune? That would be impossible if it's a signal really on the 17m band; it might be possible if the signal is really coming in at the I.F.

That's a good thought, Steve. Another person asked "what is the spacing of the signals", and I should have asked that as well. I just "assumed" that this happened every so many kHz. Does it? If so, what IS the spacing?

What is the make and model of the receiver that is picking up this noise?

First thing is that I don't hear it here, so it is probably local. What is needed is a directional antenna in the area where the signal is heard!Have you tried to build a small loop and DF this?A little local help might be in order. I do see that there are 19 clubs listed within 25 miles of your zip, and that the Twin City DX Assn has an RFI/TVI team... you might ask if they would like to get involved! They probably already have some DF antennas built!Give them a call.73s.

1. The sound level varies. On parts of the band it is loud enough to cover another normal ham transmission. Other times it is in the background and I can hear a normal transmission. It is loudest at 18.117 and gets progressively lower as I go up the band.

2. It is all over the band. It is still at 18.117 and seems to repeat at roughly 18.122-18.128-18.134-18.140 etc. It is not on exactly those frequencies, based on the pitch, but it moves up and down the band at about .006 intervals.

3. It never varies at all. As I tune up the band, the tone pitch drops.

4. So far, I have tried 3 portable radios and I can't hear it inside or outside unless I am near the dipole. Then it is strong, but as soon as I move further out in the yard or any distance away, it is gone. None of my portables are real HF units, just Sangean and Kaito.

5. I have heard it on my current Yaesu 5000. When I disconnect the antenna (dipole) I hear nothing.

Today, only on 17M but very clear and strong.

Thanks again guys for the help. I'll send off an email to the TCDXA people and see if they have any ideas. It really acts like a transmission of some type as it is more or less receivable based on propagation.

Now I am worried. I noticed that the signal was only there when I had the center of the coax connected. Then I noticed it was when anything was connected to the center pin, even just a 1 foot cable. Now I notice that the signal is coming from the Yaesu, as I can hear it on my Kaito when I am close to the Yaesu and only when it is turned on.

Take the rig to a friend's house and see if it replicates there. If so, it's time for service. If not, I'd be looking at power supply or anything else that connects to the radio. This does all seem a bit odd.

Recently I had a similar experience, with problem showing up via antenna, but much more when just center pin of coax connector was pushed in. Turned out to be a very local problem with antenna transfer relay with dirty contacts. Apparently was picking up some junk signals in my station (UPS, PC, Cisco switch, router, who knows).

Because you mentioned hearing with just center pin connector, or short wire, I would guess you also have a very local problem.

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